Sensing the motion of a device can be a time consuming task that requires intensive numerical processing. Additionally, motion sensing may only provide a gross measure of the motion of a device. Sensing motion of a portable object may require costly hardware and complicated numerical processing techniques.
Motion sensing using trilateration of positions, as performed by a Global Positioning System (GPS) or a hybrid position determination system, may be inadequate for sensing motion of a portable device. A GPS system or hybrid position determination system typically provides inadequate precision to sense motion of a portable device. GPS can require a great deal of time to acquire an initial position fix. Additionally, a GPS system or hybrid position determination system typically cannot determine rotational motion of a portable device.
Motion sensing systems incorporating gyroscopes can be used to sense the motion of a portable device. However, such systems are typically costly and not suitable for low cost designs. The costs associated with gyroscopes used in motion sensing may exceed a perceived value of the entire portable device.